The high-stakes argument comes just as a long-standing shareholder agreement between Maple Leaf's two largest shareholders, Teachers and McCain Capital Corp., expired Wednesday.

Teachers has already approached prospective buyers for its stake in the consumer products giant, according to sources. On Wednesday, the pension plan said the poison pill, or shareholder rights plan, blocks it from exercising its rights.

Jeff Lefler, the Executive Director of National Bread Network, says we raised our concerns on the change in controlling shareholders of Maple Leaf Foods when the Ontario Teachers' Pension Plan (OTPP) announced that, after a 15-year relationship, they planned to sell their 35% interest.

"We have fears that hedge funds or other investors would only have a short-term interest in the company and a hostile takeover bid may be harmful to long-term stakeholders."